Hidden Influence Inequality: New Approach to Quantum Theory

Trying to explain quantum “spooky action at a distance” using any kind of signal puts Einstein’s relativity against our concept of a smooth spacetime. (Timothy Yeo/CQT, National University of Singapore)

Since quantum physics was invented early last century, it has conformed to Einstein’s theory of relativity.

The “nonlocal” behavior seen in quantum systems, such as entangled particles, appears to violate space and time.

A new experiment based on a “hidden influence inequality” can test quantum signals directly to see whether our universe is fundamentally nonlocal, with every part instantly connected to any other part.

“We are interested in whether we can explain the funky phenomena we observe without sacrificing our sense of things happening smoothly in space and time,” said study co-author Jean-Daniel Bancal at the National University of Singapore, in a press release.

Such signals would be moving over 10,000 times light-speed, but would not violate relativity if they remain hidden.

The researchers considered what behaviors are possible for four particles connected by hidden influences traveling at an arbitrary finite speed.

Mathematically, these constraints define an 80-dimensional shape with the shadow it casts in 44 dimensions, forming the boundary to test hidden influence inequality.

“Our result gives weight to the idea that quantum correlations somehow arise from outside space-time, in the sense that no story in space and time can describe them,” said study co-author Nicolas Gisin at Switzerland’s University of Geneva, in the release.

Four particles have already been entangled, so this theory could be tested to produce a single number. If nature follows standard relativistic laws, the result would be 7, but if it behaves according to quantum theory, the limit could go up to 7.3.